The present invention is in the field generally of communication in packet networks, particularly in the area of Layer 3 Virtual Private Networks (also known as IP VPN) accomplished over the well-known Internet network. In packet routing in the Internet network, and with private routers connected to the Internet, certain well-known protocols are used to manage tasks, such as maintenance of routing tables describing the moment-to-moment topology of the network, for the purpose of selecting next destination for packets at any node, for example. One such protocol is known in the art as Border Gateway Protocol (BGP), and BGP is involved intimately with the present invention in various embodiments. BGP is well-known, so no effort is made in this disclosure to teach the concepts and procedures for BGP, except for occasional reference to the protocol and its high-level features.
An application of IP VPN growing in demand, and therefore an object of attention by developers and manufacturers of Internet routers and providers of Internet services, is in provision of services at edge routers for peering with virtual private routed networks (VPRN). A VPRN may be thought of as a network within the Internet network, wherein a defined enterprise or organization may use the network almost as though there were no other participants. This is of great value to geographically diverse organizations, because such organizations may have connections among remote campuses almost as though all the network nodes were in the same building. The necessary computer power to manage such a network is greatly reduced over simply sharing the Internet on an individual basis, because the necessary topology and communication between intermediate hops, and the like, is greatly reduced as well.